Heparanase specific molecular probes and their use in research and medical applications

ABSTRACT

A variety of heparanase specific molecular probes which can be used for research and medical applications including diagnosis and therapy. Specific applications include the use of a heparanase specific molecular probe for detection of the presence, absence or level of heparanase expression; the use of a heparanase specific molecular probe for therapy of a condition associated with expression of heparanase; the use of a heparanase specific molecular probe for quantification of heparanase in a body fluid; the use of a heparanase specific molecular probe for targeted drug delivery; and the use of a heparanase specific molecular probe as a therapeutic agent.

This is a continuation of U.S. patent application Ser. No. 09/944,602,filed Sep. 4, 2001, which is a continuation of U.S. patent applicationSer. No. 09/759,207, filed Jan. 16, 2001, which is a continuation ofU.S. patent application Ser. No. 09/322,977, filed Jun. 1, 1999, nowU.S. Pat. No. 6,531,129, issued Mar. 11, 2003, which is a divisional ofU.S. patent application Ser. No. 09/071,739, filed May 1, 1998, now U.S.Pat. No. 6,177,545, issued Jan. 23, 2001, which is acontinuation-in-part of U.S. patent application Ser. No. 08/922,170,filed Sep. 2, 1997, now U.S. Pat. No. 5,968,822, issued Oct. 19, 1999.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to heparanase specific molecular probestheir use in research and medical applications. More particularly, thepresent invention relates to the use of heparanase specific molecularprobes, such as anti-heparanase antibodies (both poly- and monoclonal)and heparanase gene (hpa) derived nucleic acids, including, but notlimited to, PCR primers, antisense oligonucleotide probes, antisense RNAprobes, DNA probes and the like for detection and monitoring ofmalignancies, metastasis and other non-malignant conditions, efficiencyof therapeutic treatments, targeted drug delivery and therapy.

Heparan sulfate proteoglycans (HSPGs): HSPGs are ubiquitousmacromolecules associated with the cell surface and extracellular matrix(ECM) of a wide range of cells of vertebrate and invertebrate tissues(1-5). The basic HSPG structure consists of a protein core to whichseveral linear heparan sulfate chains are covalently attached. Thepolysaccharide chains are typically composed of repeating hexuronic andD-glucosamine disaccharide units that are substituted to a varyingextent with N- and O-linked sulfate moieties and N-linked acetyl groups(1-5). Studies on the involvement of ECM molecules in cell attachment,growth and differentiation revealed a central role of HSPGs in embryonicmorphogenesis, angiogenesis, metastasis, neurite outgrowth and tissuerepair (1-5). The heparan sulfate (HS) chains, unique in their abilityto bind a multitude of proteins, ensure that a wide variety of effectormolecules cling to the cell surface (4-6). HSPGs are also prominentcomponents of blood vessels (3). In large vessels they are concentratedmostly in the intima and inner media, whereas in capillaries they arefound mainly in the subendothelial basement membrane where they supportproliferating and migrating endothelial cells and stabilize thestructure of the capillary wall. The ability of HSPGs to interact withECM macromolecules such as collagen, laminin and fibronectin, and withdifferent attachment sites on plasma membranes suggests a key role forthis proteoglycan in the self-assembly and insolubility of ECMcomponents, as well as in cell adhesion and locomotion. Cleavage of HSmay therefore result in disassembly of the subendothelial ECM and hencemay play a decisive role in extravasation of blood-borne cells (7-9). HScatabolism is observed in inflammation, wound repair, diabetes, andcancer metastasis, suggesting that enzymes which degrade HS playimportant roles in pathologic processes.

Involvement of heparanase in tumor cell invasion and metastasis:Circulating tumor cells arrested in the capillary beds of differentorgans must invade the endothelial cell lining and degrade itsunderlying basement membrane (BM) in order to escape into theextravascular tissue(s) where they establish metastasis (10). Severalcellular enzymes (e.g., collagenase IV, plasminogen activator, cathepsinB, elastase) are thought to be involved in degradation of the BM (10).Among these enzymes is an endo-β-D-glucuronidase (heparanase) thatcleaves HS at specific intrachain sites (7, 9, 11-12). Expression of aHS degrading heparanase was found to correlate with the metastaticpotential of mouse lymphoma (11), fibrosarcoma and melanoma (9) cells.Treatment of experimental animals with heparanase inhibitors (i.e.non-anticoagulant species of low MW heparin) markedly reduced (>90%) theincidence of lung metastases induced by B16 melanoma, Lewis lungcarcinoma and mammary adenocarcinoma cells (8, 9, 13).

Heparanase activity could not be detected in normal stromal fibroblasts,mesothelial, endothelial and smooth muscle cells derived from noncancerous biopsies and effusions (12). These observations indicate thatheparanase expression may serve as a marker for tumor cells and inparticular for those which are highly invasive or potentially invasive.If the same conclusion can be reached by immunostaining of tissuespecimens, anti-heparanase antibodies may be applied for early detectionand diagnosis of metastatic cell populations and micro-metastases.

Our studies on the control of tumor progression by its localenvironment, focus on the interaction of cells with the extracellularmatrix (ECM) produced by cultured corneal and vascular endothelial cells(EC) (14, 15). This ECM closely resembles the subendothelium in vivo inits morphological appearance and molecular composition. It containscollagens (mostly type III and IV, with smaller amounts of types I andV), proteoglycans (mostly heparan sulfate- and dermatansulfate-proteoglycans, with smaller amounts of chondroitin sulfateproteoglycans), laminin, fibronectin, entactin and elastin (13, 14). Theability of cells to degrade HS in the ECM was studied by allowing cellsto interact with a metabolically sulfate labeled ECM, followed by gelfiltration (Sepharose 6B) analysis of degradation products released intothe culture medium (11). While intact HSPG are eluted next to the voidvolume of the column (Kav<0.2, Mr˜0.5×10⁶), labeled degradationfragments of HS side chains are eluted more toward the Vt of the column(0.5<kav<0.8, Mr=5-7×10³) (11).

Possible involvement of heparanase in tumor angiogenesis: Fibroblastgrowth factors are a family of structurally related polypeptidescharacterized by high affinity to heparin (16). They are highlymitogenic for vascular endothelial cells (EC) and are among the mostpotent inducers of neovascularization (16, 17). Basic fibroblast growthfactor (bFGF) has been extracted from subendothelial ECM produced invitro and from BM of the cornea, suggesting that ECM may serve as areservoir for bFGF (18). Studies on the interaction of bFGF with ECMrevealed that bFGF binds to HSPG in the ECM and can be released in anactive form by HS degrading enzymes (19, 20). Heparanase activityexpressed by platelets, mast cells, neutrophils, and lymphoma cellsreleases active bFGF from ECM and BM (20), suggesting that heparanasemay not only function in cell migration and invasion, but may alsoelicit an indirect neovascular response (18). These results suggest thatthe ECM HSPGs provide a natural storage depot for bFGF and possiblyother heparin-binding growth promoting factors. Displacement of bFGFfrom its storage within ECM may therefore provide a novel mechanism forinduction of neovascularization in normal and pathological situations(6, 18).

Expression of heparanase by cells of the immune system: Heparanaseactivity correlates with the ability of activated cells of the immunesystem to leave the circulation and elicit both inflammatory andautoimmune responses. Interaction of platelets, granulocytes, T and Blymphocytes, macrophages and mast cells with the subendothelial ECM isassociated with degradation of heparan sulfate (HS) by heparanaseactivity (7). The enzyme is released from intracellular compartments(e.g., lysosomes, specific granules) in response to various activationsignals (e.g., thrombin, calcium ionophore, immune complexes, antigens,mitogens), suggesting its regulated involvement and presence ininflammatory sites and autoimmune lesions. Heparan sulfate degradingenzymes released by platelets and macrophages are likely to be presentin atherosclerotic lesions (21). Hence, cDNA probes and anti-heparanaseantibodies may be applied for detection and early diagnosis of theselesions.

Cloning and expression of the heparanase gene: The cloning andexpression of the human heparanase gene are described in U.S. patentapplication Ser. No. 08/922,170, which is incorporated by reference asif fully set forth herein. A purified fraction of heparanase isolatedfrom human hepatoma cells was subjected to tryptic digestion. Peptideswere separated by high pressure liquid chromatography and microsequenced. The sequence of one of the peptides was used to screen databases for homology to the corresponding back translated DNA sequence.This procedure led to the identification of a clone containing an insertof 1020 base pairs (bp) which included an open reading frame of 963 bpfollowed by 27 bp of 3′ untranslated region and a Poly A tail. The newgene was designated hpa. Cloning of the missing 5′ end of hpa cDNA wasperformed by PCR amplification of DNA from placenta cDNA composite. Theplasmid containing the entire heparanase cDNA was designated phpa. Thejoined cDNA fragment contained an open reading frame which encodes apolypeptide of 543 amino acids with a calculated molecular weight (MW)of 61,192 daltons. The ability of the hpa gene product to catalyzedegradation of heparan sulfate (HS) in vitro was examined by expressingthe entire open reading frame of hpa in High five and Sf21 insect cells,using the Baculovirus expression system. Extracts of infected cells wereassayed for heparanase activity. For this purpose, cell lysates wereincubated with sulfate labeled, ECM-derived HSPG (peak I), followed bygel filtration analysis (Sepharose 6B) of the reaction mixture. Whilethe substrate alone consisted of high molecular weight (MW) material,incubation of the HSPG substrate with lysates of cells infected with hpacontaining virus resulted in a complete conversion of the high MWsubstrate into low MW labeled heparan sulfate degradation fragments.

In subsequent experiments, the labeled HSPG substrate was incubated withthe culture medium of infected High Five and Sf21 cells. Heparanaseactivity, reflected by the conversion of the high MW HSPG substrate intolow MW HS degradation fragments, was found in the culture medium ofcells infected with the pFhpa virus, but not the control pF1 virus.Altogether, these results indicate that the heparanase enzyme isexpressed in an active form by cells infected with Baculoviruscontaining the newly identified human hpa gene. In other experiments, wehave demonstrated that the heparanase enzyme expressed by cells infectedwith the pFhpa virus is capable of degrading HS complexed to othermacromolecular constituents (e.g., fibronectin, laminin, collagen)present in a naturally produced intact ECM, in a manner similar to thatreported for highly metastatic tumor cells or activated cells of theimmune system.

Purification of the recombinant heparanase enzyme: The purification ofthe human heparanase gene are described in U.S. patent application Ser.No. 08/922,170, which is incorporated by reference as if fully set forthherein. Sf21 insect cells were infected with pFhpa virus and the culturemedium was applied onto a heparin-Sepharose column. Fractions wereeluted with a salt gradient (0.35-2 M NaCl) and tested for heparanaseactivity and protein profile (SDS/PAGE followed by silver staining).Heparanase activity correlated with the appearance of a protein band ofabout 63 kDa in fractions 19-24, consistent with the expected MW of thehpa gene product. Active fractions eluted from heparin-Sepharose werepooled, concentrated and applied onto a Superdex 75 FPLC gel filtrationcolumn. Aliquots of each fraction were tested for heparanase activityand protein profile. A correlation was found between the appearance of amajor protein of about 63 kDa in fractions 4-7 and heparanase activity.This protein was not present in medium conditioned by controlnon-infected Sf21 cells and subjected to the same purification protocol.

Research on the involvement of heparanase/HS in tumor cell metastasisand angiogenesis has been handicapped by the lack of biological tools(i.e., molecular probes, antibodies) to explore a causative role ofheparanase in disease. U.S. patent application Ser. No. 08/922,170offers, for the first time, a good opportunity to elucidate the enzyme'sinvolvement in tumor metastasis and angiogenesis and the relateddiagnostic applications.

On the basis of the examples described below, it appears that cDNA andRNA probes, PCR primers, and anti-heparanase antibodies (heparanasespecific molecular probes) can be applied to detect the heparanase geneand protein and hence for early diagnosis of micrometastases, autoimmunelesions, renal failure and atherosclerotic lesions using biopsyspecimens, plasma samples, and body fluids.

Specificity and advantages over other reported antibodies: A variety ofblood, tumor cells and certain normal cells have been shown to producesignificant amounts of heparanase activity. The purification tohomogeneity and characterization of mammalian heparanases has beendifficult, primarily due to the lack of a convenient assay. Most reportscontain only partial description with conflicting information. Oosta, etal. (22) described the purification of a human platelet heparanase withan estimated molecular mass of 134 kDa expressing an endoglucuronidaseactivity. Hoogewert, et al. (23) reported the purification of a 30 kDahuman platelet heparanase which was shown to be an endoglucosaminidasethat cleave both heparin and heparan sulfate essentially todisaccharides. They claimed that the holoenzyme consists of foursubunits, each closely related to the CXC chemokines CTAPIII, NAP-2 andβ-thromboglobulin (23). Freeman and Parish (24) have purified tohomogeneity a 50 kDa platelet heparanase exhibiting endoglucuronidaseactivity. Likewise heparanase enzyme purified from human placenta andfrom hepatoma cell line (U.S. Pat. No. 5,362,641) had a molecular massof approximately 48 kDa. A similar molecular weight was determined bygel filtration analysis of partially purified heparanase enzymesisolated form human platelets, human neutrophils and mouse B16 melanomacells (our unpublished data). In contrast, heparanase purified from B16melanoma cells by Nakajima, et al. (9, 26) had a molecular weight of 96kDa. The latter enzyme has been localized immunochemically to the cellsurface and cytoplasm of human melanoma lesions using a polyclonalantiserum (26) and in tertiary granules in neutrophils using monoclonalantibodies (26a), both directed against a putative amino terminalsequence from purified B16F10 melanoma cell heparanase (26). However,the melanoma heparanase amino terminal sequence was found to becharacteristic of a 94 kDa glucose-regulated protein (GRP94/endoplasmin)that functions as a molecular chaperone which lacks heparanase activity(27). This result and a recent study using anti-endoplasmin antibody(28) suggest that the endoplasmin-like 98 kDa protein found in purifiedmelanoma heparanase preparations is a contaminant (27, 28). This callsinto question the previous heparanase immunolocalization studies carriedout using the B16 melanoma heparanase amino terminal peptide antiserum(26). Likewise, antiserum directed against the amino terminal sequenceof CTAP III was applied to immunolocalize the heparanase enzyme inbiopsy specimens of human prostate and breast carcinomas (29, 30).Again, the validity of the results is questionable, since thepossibility that CTAP III is a contaminant of the platelet preparationwas not excluded. First, attempts to express heparanase activeCTAPIII/NAP2 protein were unsuccessful and the recombinant CTAPIII/NAP2chemokines failed to exhibit heparanase activity. Second, western blotanalysis of the platelet enzyme purified by Freeman and Parish (24) withantibodies against human β-thromboglobulin or platelet factor-4demonstrated that these and related proteins (e.g., CTAP-III and NAP-2)were not present in the purified platelet heparanase preparations (24).Moreover, while heparanase activity can be detected in purifiedpreparations of β-thromboglobulin, it is probably due to contaminationwith the “classical” platelet heparanase since it exhibited anendo-beta-D-glucuronidase activity rather than an endoglucosaminidaseactivity (23), as reported by Hoogewerf et al. (Pikas et al. manuscriptsubmitted for publication).

Our studies on the immunolocalization of CTAPIII in human biopsyspecimens revealed a preferential localization of CTAP-III in cells(i.e., vascular endothelia cells, keratinocytes) that failed to expressheparanase activity and vice versa. Finally, none of the sequencespublished by Hoogewerf et al (platelet CTAP-III/NAP-2) (23) or Jin etal. (B16 melanoma) (26) nor sequences of the bacterial heparin/heparansulfate degrading enzymes (hep I & III) (30a) were found in ourrecombinant human heparanase that was cloned and expressed on the basisof sequences derived from the purified human placenta and hepatomaheparanases.

Several years ago we prepared rabbit polyclonal antibodies directedagainst our partially purified preparation of human placenta heparanase.These antibodies, referred to in U.S. Pat. No. 5,362,641, were laterfound to be directed against plasminogen activator inhibitor type I(PAI-1) that was co-purified with the placental heparanase. Thesefindings led to a modification of the original purification protocol toremove the PAI-1 contaminant.

Collectively, it is evident that so far no one had succeeded ineliciting anti-heparanase antibodies.

Unlike the above described information, both the polyclonal andmonoclonal antibodies described hereinunder were raised, for the firsttime, against a purified, highly active, recombinant enzyme. As furthershown below these antibodies specifically recognizes the heparanaseenzyme in cell lysates and conditioned media and does not cross-reactwith β-thromboglobulin, NAP-2, PAI-1 or bacterial heparinases I and III.They do recognize the mouse B16-F10 heparanase, the human plateletheparanases, and the heparanase enzymes produced by several human tumorcell lines and Chinese hamster ovary (CHO) cells. By virtue of beingproduced against a purified recombinant enzyme and their specificity,these antibodies appear highly appropriate for diagnostic purposes suchas immunohistochemistry of biopsy specimens and quantitative ELISA ofbody fluids (e.g., plasma, urine, pleural effusions, etc.). Similarly,as presented in the Examples section hereinunder, both the molecularprobes for in situ determination of the tissue distribution of the hpagene and the cDNA primers for detection of the hpa mRNA in normal andmalignant cells of human origin (e.g., leukemia and lymphoma cells,melanoma cells) can be applied, for the first time, for diagnosis ofearly events in tumor progression, metastatic spread and response totreatment.

SUMMARY OF THE INVENTION

According to the present invention there are provided heparanasespecific molecular probes and their use in use in research and medicalapplications including diagnosis and therapy.

According to further features in preferred embodiments of the inventiondescribed below, there is provided an antibody elicited by a heparanaseprotein or an immunogenical portion thereof, the antibody specificallybinds heparanase.

According to still further features in the described preferredembodiments the heparanase protein is recombinant.

According to still further features in the described preferredembodiments the elicitation is through in vivo or in vitro techniques,the antibody having been prepared by a process comprising the steps of(a) exposing cells capable of producing antibodies to the heparanaseprotein or the immonogenical part thereof and thereby generatingantibody producing cells; (b) fusing the antibody producing cells withmyeloma cells and thereby generating a plurality of hybridoma cells eachproducing monoclonal antibodies; and (c) screening the plurality ofmonoclonal antibodies to identify a monoclonal antibody whichspecifically binds heparanase.

According to still further features in the described preferredembodiments the antibody is selected from the group consisting of apolyclonal antibody and a monoclonal antibody.

According to still further features in the described preferredembodiments the polyclonal antibody is selected from the groupconsisting of a crude polyclonal antibody and an affinity purifiedpolyclonal antibody.

According to further features in preferred embodiments of the inventiondescribed below, there is provided an oligonucleotide comprising anucleic acid sequence specifically hybridizable with heparanase encodingnucleic acid.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a pair of polymerase chain reactionprimers comprising a sense primer and an antisense primers, each of theprimers including a nucleic acid sequence specifically hybridizable withheparanase encoding nucleic acid.

According to further features in preferred embodiments of the inventiondescribed below, there is provided an antisense nucleic acid (RNA orDNA) molecule comprising a nucleic acid sequence specificallyhybridizable with heparanase messenger RNA.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a sense nucleic acid (RNA or DNA)molecule comprising a nucleic acid sequence specifically hybridizablewith heparanase antisense RNA.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a method of in situ detectinglocalization and distribution of heparanase expression in a biologicalsample comprising the step of reacting the biological sample with adetectable heparanase specific molecular probe and detecting thelocalization and distribution of the detectable heparanase specificmolecular probe.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a method of detecting heparanaseexpression in a biological sample comprising the step of reacting thebiological sample with a detectable heparanase specific molecular probeand detecting said detectable heparanase specific molecular probe.Protein and nucleic acid dot blot application are envisaged.

According to still further features in the described preferredembodiments the biological sample is selected from the group consistingof cells and tissues.

According to still further features in the described preferredembodiments the biological sample is malignant.

According to still further features in the described preferredembodiments the malignancy is selected from the group consisting of asolid tumor and a hematopoietic tumor.

According to still further features in the described preferredembodiments the solid tumor is selected from the group consisting ofcarcinoma, adenocarcinoma, squameous cell carcinoma, teratocarcinoma,mesothelioma and melanoma, and further wherein the hematopoietic tumoris selected from the group consisting of lymphoma and leukemia.

According to still further features in the described preferredembodiments the solid tumor is a primary tumor, or a metastasis thereof,and is originated from an organ selected from the group consisting ofliver, prostate, bladder, breast, ovary, cervix, colon, skin, intestine,stomach, uterus, pancreas.

According to still further features in the described preferredembodiments the detectable heparanase specific molecular probe isselected from the group consisting of a nucleic acid sequencehybridizable with heparanase encoding nucleic acid and ananti-heparanase antibody capable of specifically binding heparanase.

According to still further features in the described preferredembodiments the nucleic acid sequence hybridizable with heparanaseencoding nucleic acid is selected from the group consisting of asynthetic oligonucleotide, an antisesnse heparanase RNA and heparanaseDNA labeled by a detectable moiety.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a method of detecting heparanaseprotein in a body fluid of a patient comprising the steps of reactingthe body fluid with an anti-heparanase antibody and monitoring thereaction.

According to still further features in the described preferredembodiments the body fluid is selected from the group consisting ofplasma, urine, pleural effusions and saliva.

According to still further features in the described preferredembodiments the body fluid is of a patient suffering from a conditionselected from the group consisting of cancer, renal disease anddiabetes.

According to still further features in the described preferredembodiments the renal disease is associated with diabetes.

According to still further features in the described preferredembodiments the anti-heparanase antibody is selected from the groupconsisting of a monoclonal antibody and a poly clonal antibody.

According to still further features in the described preferredembodiments reacting the body fluid with the anti-heparanase antibody iseffected in solution.

According to still further features in the described preferredembodiments reacting the body fluid with the anti-heparanase antibody iseffected on a substrate capable of adsorbing proteins present in thebody fluid.

According to still further features in the described preferredembodiments the body fluid is of a patient suffering from myeloma,breast carcinoma, metastatic breast carcinoma, hemorrhagic nephritis,nephrotic syndrome, normoalbuminuric type I diabetes, microalbuminurictype I diabetes, kidney disorder, inflammation, sepsis, inflammatory andautoimmune disease.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a method of detecting the presence,absence or level of heparanase transcripts in a biological samplecomprising the steps of (a) extracting messenger RNA from the biologicalsample, thereby obtaining a plurality of messenger RNAs; (b) reversetranscribing the plurality of messenger RNAs into a plurality ofcomplementary DNAs; (c) contacting the plurality of complementary DNAswith a pair of heparanase specific polymerase chain reaction primers,nucleoside triphosphates and a thermostable DNA polymerase; (d)performing a polymerase chain reaction; and (e) detecting the presence,absence or level of the polymerase chain reaction product.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a method of detecting heparanasemessenger RNA in a biological sample comprising the steps of reversetranscribing the messenger RNA into complementary DNA, contacting thecomplementary DNA with polymerase chain reaction oligonucleotideshybridizable to heparanase encoding nucleic acid, performing apolymerase chain reaction and monitoring for heparanase specificpolymerase chain reaction products.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a method of detecting the presence,absence or level of heparanase protein in a biological sample comprisingthe steps of (a) extracting proteins from the biological sample, therebyobtaining a plurality of proteins; (b) size separating the proteins; (c)interacting the size separated proteins with an anti-heparanaseantibody; and (d) detecting the presence, absence or level of theinteracted anti-heparanase antibody.

According to still further features in the described preferredembodiments the anti-heparanase antibody is selected from the groupconsisting of a polyclonal antibody and a monoclonal antibody.

According to still further features in the described preferredembodiments the size separation is effected by electrophoresis.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a method of targeted drug delivery toa tissue of a patient, the tissue expressing heparanase, the methodcomprising the steps of providing a complex of a drug directly orindirectly linked to an anti-heparanase antibody and administering thecomplex to the patient.

According to further features in preferred embodiments of the inventiondescribed below, there is provided a method of treating a patient havinga condition associated with heparanase expression comprising the step ofadministering an anti-heparanase antibody to the patient.

It is an object of the present invention to use a heparanase specificmolecular probe for detection of the presence, absence or level ofheparanase expression.

It is another object of the present invention to use a heparanasespecific molecular probe for therapy of a condition associated withexpression of heparanase.

It is yet another object of the present invention to use a heparanasespecific molecular probe for quantification of heparanase in a bodyfluid.

It is still another object of the present invention to use a heparanasespecific molecular probe for targeted drug delivery.

It is another object of the present invention to use a heparanasespecific molecular probe as a therapeutic agent.

The present invention successfully addresses the shortcomings of thepresently known configurations by providing a variety of heparanasespecific molecular probes which can be used for research and medicalapplications including diagnosis and therapy.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention herein described, by way of example only, with referenceto the accompanying drawings, wherein:

The file of this patent contains at least one drawing(s) executed incolor. Copies of this patent with color photograph(s) will be providedby the Patent and Trademark Office upon request and payment of necessaryfee.

FIG. 1 demonstrates the expression of the human heparanase gene by humanbreast carcinoma cell lines with different metastatic potentials. TotalRNA was isolated and subjected to semi quantitative RT-PCR (28 cycles)using human heparanase primers (hep) and primers for the GAPDHhousekeeping gene. Reactions without reverse transcriptase demonstratedno amplification of genomic DNA contamination in the RNA samples (notshown). Lane 1, Non metastatic MCF-7 cells, lane 2, moderate metastaticMDA-231 cells, lane 3, highly aggressive MDA-435 cells, lane 4, minimalmetastatic ZR-75 cells, lane 5, moderate metastatic MCF-ANeoT cells,lane 6, highly metastatic MCF-T₆ 3B cells; lane 7, DNA molecular weightmarker VI (Boehringer Mannheim).

FIGS. 2 a-b demonstrate heparanase activity expressed by human breastcarcinoma cell lines with different metastatic potentials. Breastcarcinoma cell lysates of the above described cell lines were incubated(24 hours, 37° C., pH 6.2) with ³⁵S-HSPG isolated from intactsubendothelial ECM. Heparanase mediated conversion of the heparansulfate substrate (peak I) into low MW degradation fragments (peak II)was analyzed by gel filtration on Sepharose 6B. Expression of the humanhpa gene correlates with heparanase activity and metastasis inexperimental animals.

FIGS. 3 a-f demonstrate detection of hpa mRNA by in situ hybridizationin specimens of normal and malignant human breast tissue with antisenseheparanase RNA probe: invasive carcinoma of the breast, pre-malignantfibrocystic breast tissue, adenocarcinoma of the breast, invasive breastcarcinoma surrounding the area of tumor necrosis (not stained), normalbreast tissue-reduction mammoplasty (antisense hpa probe), and normalbreast tissue-reduction mammoplasty (control sense probe), respectively.

FIG. 4 demonstrate heparanase activity expressed by human prostatecarcinoma cell lines. Expression of the human hpa gene by normal andmalignant human prostate cells. Total RNA was isolated and subjected toRT-PCR using the appropriate human hpa primers (hep) and primers for theGAPDH housekeeping gene. Reactions without reverse transcriptasedemonstrated no genomic DNA contamination in the RNA samples (notshown). Lane 1, metastatic DU145 human prostate carcinoma cells, lane 2,metastatic PC3 human prostate carcinoma cells, lane 3, normal humanprostate tissue (biopsy specimen), lane 4, DNA molecular weight markerVI (Boehringer Mannheim).

FIG. 5 demonstrate the expression of the hpa gene by high and lowmetastatic human bladder carcinoma and mouse T lymphoma cell lines.Total RNA was isolated and subjected to RT-PCR using human hpa primers.Lane 1, non metastatic MBT2 human bladder carcinoma cells, lane 2,highly metastatic T50 variant of MBT2 cells, lane 3, non-metastatic Ebmouse T-lymphoma, lane 4, highly metastatic ESb variant of the Eb mouseT-lymphoma cells, lane 5, DNA molecular weight marker VI (BoehringerMannheim). −RT: negative control, without reverse transcriptase, P: nonamplified primers.

FIGS. 6 a-c demonstrate heparanase activity expressed by high and lowmetastatic human bladder carcinoma cells. Media conditioned by low(MBT2) and high (T50) metastatic human bladder carcinoma cells wereincubated (24 hours, 37° C., pH 6.2) with ³⁵S-HSPG isolated from intactsubendothelial ECM. Heparanase mediated conversion of the heparansulfate substrate (peak I, ss 47) into low molecular weight degradationfragments (peak II) was analyzed by gel filtration on Sepharose 6B.Expression of the human hpa gene correlates with heparanase activity andmetastasis in experimental animals.

FIG. 7 demonstrate expression of the hpa gene by high and low metastaticB16 mouse melanoma cell lines. Total RNA was isolated and subjected toRT-PCR using hpa primers (hep) and primers for the GAPDH housekeepinggene. Reactions without reverse transcriptase demonstrated no genomicDNA contamination in the RNA samples. Lane 1, highly metastatic B16-F10mouse melanoma cells, lane 2, low metastatic B16-F1 mouse melanomacells, lane 3, DNA molecular weight marker VI (Boehringer Mannheim).

FIG. 8 a demonstrate expression of the hpa gene by biopsy specimens frommalignant human melanoma tumors and non-malignant benign nevus tissuewhich were processed for cell culture. Total RNA was isolated fromsubconfluent cultures and subjected to RT-PCR using human specific hpaprimers (hep). Representative cases are shown. Lane 1, malignantmelanoma, lane 2, non-malignant nevus tissue, lane 3, hpa-pcDNA plasmid(positive control), lane 4, negative control (no RNA), lane 5, DNAmolecular weight marker VI (Boehringer Mannheim). Reactions withoutreverse transcriptase (−RT) demonstrated no genomic DNA contamination inthe RNA samples.

FIG. 8 b demonstrates heparanase activity expressed by cultured cellsderived from malignant melanoma (patient M-24) and non-malignant nevustissue (patient M-31). Cultured cells were seeded on sulfate-labeledECM. Labeled degradation fragments released into the incubation mediumwere subjected to gel filtration on sepharose 6B.

FIGS. 9 a-f demonstrate detection of hpa mRNA by in situ hybridizationin specimens of human malignant melanoma and normal nevus. FIGS. 9 a, cand d—metastatic human melanoma (3 different patients), FIG. 9 b—nonmalignant nevus tissue. Labeling is not seen in the nevus tissue, ascompared to intense staining of the metastatic melanoma. FIGS. 9 e andf—same sections as in FIGS. c and d stained with hematoxylin-eosine.

FIGS. 10 a-f demonstrate detection of hpa mRNA by in situ hybridizationin specimens of normal and malignant human liver. Hepatocellularcarcinoma (×200), hepatocellular carcinoma (×1000), liveradenocarcinoma, normal adult liver, embryonic liver and control sensestaining of embryonic liver are shown respectively. Labeling is not seenin normal liver cells as compared to intense staining of embryonic andmalignant liver cells.

FIGS. 11 a-f demonstrate detection of hpa mRNA by in situ hybridizationin specimens of normal and malignant human tissues. Adenocarcinoma ofthe ovary, normal ovary, squameous cell carcinoma of the cervix, normalcervix, colon adenocarcinoma and normal small intestine are shownrespectively.

FIGS. 12 a-f demonstrate detection of hpa mRNA by in situ hybridizationin specimens of various human tumors. Positive staining of the hpa genewas clearly seen in adenocarcinoma of the stomach, teratocarcinoma, welldifferentiated endometrial adenocarcinoma, adenocarcinoma of thepancreas, mesothelioma, FIGS. 12 a-e, respectively. Control, sensestaining of human mesothelioma is shown in FIG. 12 f.

FIGS. 13 a-b demonstrate expression of heparanase in human leukemias andlymphomas. Peripheral white blood cells of patients with various typesof leukemia and lymphoma were isolated and tested for expression of thehuman hpa gene. For this purpose, total RNA was isolated and subjectedto RT-PCR using human specific hpa primers. Reactions without reversetranscriptase demonstrated no genomic DNA contamination in the RNAsamples. Peripheral white blood cells of different patients with chroniclymphocytic leukemia (FIG. 13 a, lanes 1-5) were isolated and tested forexpression of the human hpa gene. 13a Lane 6, hpa-pcDNA plasmid(positive control), lane 7, negative control (no reverse transcriptase),lane 8, DNA molecular weight marker VI (Boehringer Mannheim).Representative patients with various types of leukemia and lymphoma areshown in FIG. 13 b. Lane 1, acute myelocytic leukemia, lane 2, Chroniclymphocytic leukemia (atypical B cell), lane 3, acute myelocyticleukemia (M5), lane 4, hairy cell leukemia, lane 5, non-hodjkin lymphoma(mature B cells), lane 6, non-hodjkin lymphoma (mature B cells), lane 7,chronic lymphocytic leukemia (stage I), lane 8, acute myelocyticleukemia (M2), lane 9, chronic myelocytic leukemia, lane 10, chroniclymphocytic leukemia (stage II), lane 11, acute lymphocytic leukemia,lane 12, chronic lymphocytic leukemia (stage III), lane 13, acutemyelocytic leukemia (M1), lane 14, acute myelocytic leukemia (M3), lane15, hpa-pcDNA plasmid (positive control), lane 16, negative control (noreverse transcriptase), lane 17, DNA molecular weight marker VI(Boehringer Mannheim).

FIG. 14 demonstrates no expression of the hpa gene by normal humanumbilical cord white blood cells. Total RNA was isolated and subjectedto RT-PCR using hpa primers (hep) and primers for the GAPDH housekeepinggene. Reactions without reverse transcriptase demonstrated no genomicDNA contamination in the RNA samples. Lanes 1-6, white blood cellpreparations from 6 different umbilical cords, lane 7, hpa-pcDNA plasmid(positive control), lane 8, negative control (no reverse transcriptase),lane 9, DNA molecular weight marker VI (Boehringer Mannheim).

FIG. 15 demonstrates expression of the hpa gene by leukemia and lymphomacell lines. Total RNA was isolated and subjected to RT-PCR using hpaprimers (hep) and primers for the GAPDH housekeeping gene. Reactionswithout reverse transcriptase demonstrated no genomic DNA contaminationin the RNA samples. Lane 1, normal B lymphoblastoid cell line (Monga),lane 2, Burkitt B lymphoma (Raji), lane 3, Burkitt B lymphoblasts(Daudi), lane 4, Burkitt B lymphoblasts (non Ebv, DG-75), lane 5,erythroleukemia (K-562), lane 6, pre B lymphoma (nalm₆), M=DNA molecularweight marker VI (Boehringer Mannheim).

FIGS. 16 a-h demonstrate urinary heparanase activity. Urine samples (o)of healthy donor (16 d) and patients with multiple myeloma (16 a),bilateral breast carcinoma (16 b), metastatic breast carcinoma (16 c),hemorrhagic nephritis (16 e) nephrotic syndrome (16 f), normoalbuminuric(16 g) and microalbuminuric type I diabetes (16 h) were incubated (24hours, 37° C., pH 6.2) with ³⁵S-HSPG (50 μl) isolated from intactsubendothelial ECM (♦). Heparanase mediated conversion of the heparansulfate substrate (peak I) into low molecular weight degradationfragments (peak II) was analyzed by gel filtration on Sepharose 6B.

FIGS. 17 a-b demonstrate Western blots of extracts of cells expressingvarious segments of heparanase as detected with polyclonal antiheparanase antibodies. 17 a—antiserum from rabbit 7640, 17 b—antiserumfrom rabbit 7644. Lane 1, E. coli BL21(DE3)pLysS cells transfected withpRSET, lane 2, E. coli BL21(DE3)pLysS cells transfected with pRSETcontaining the heparanase entire open reading frame (543 amino acids, SEID NOs: 2 and 3), lane 3, E. coli BL21(DE3)pLysS cells transfected withpRSEThpaBK containing 414 amino acids of the heparanase open readingframe (amino acids 130-543 of SEQ ID NOs: 2 and 3), lane 4, E. coliBL21(DE3)pLysS cells transfected with pRSEThpaBH containing 302 aminoacids of the heparanase open reading frame (amino acids 130-431 of SEQID NOs: 2 and 3), lane 5, molecular size markers, lane 6, medium of Sf21insect cells infected with recombinant Baculovirus pFhpa containing theheparanase entire open reading frame (543 amino acids, SEQ ID NOs: 2 and3), lane 7, Sf21 insect cells infected with recombinant baculovirus withno insert. Proteins were separated on 10% SDS-PAGE, antisera werediluted 1:1,000. Detection was performed by ECL (Amersham) according tothe manufacturer's instructions. Size in kDa is shown to the right, aswas determined using prestained SDS-PAGE standards, Bio-Rad, CA.

FIG. 18 demonstrates Western blot using affinity purified polyclonalantibodies with heparanase expressed in various expression systems. Lane1, medium of Sf21 insect cells infected with recombinant BaculoviruspFhpa, lane 2, cell extract of a Chinese hamster ovary (CHO) clonestably transfected with a vector containing no insert, lane 3, cellextract of a CHO stable clone transfected with hpa cDNA, lane 4,proteins precipitated from medium of the yeast Pichia pastoristransfected with hpa cDNA. Proteins were separated on 4-20% gradientSDS-PAGE, antibody was diluted 1:100. Detection was performed by ECL(Amersham) according to the manufacturer's instructions. For CHO andPichia clones see U.S. patent application Ser. No. 09/071,618, which isincorporated by reference as if fully set forth herein. Size in kDa isshown to the right, as was determined using prestained SDS-PAGEstandards, Bio-Rad, CA.

FIGS. 19 a-b demonstrate Western blot of extracts of various cell typesusing anti-heparanase polyclonal antibodies. 19 a—crude antiserumdiluted 1:2,000, 19 b—affinity purified antibodies diluted 1:100. lane1, purified heparanase from placenta, lanes 2 and 3, cell extracts ofplatelets, insoluble and soluble fractions, respectively, lanes 4 and 5,cell extracts of neutrophils, insoluble and soluble fractions,respectively, lanes 6 and 7, cell extracts of mouse melanoma B16-F1cells, insoluble and soluble fractions, respectively. Proteins wereseparated on 8-16% gradient gel. Detection was performed by ECL(Amersham) according to the manufacturer's instructions. Size in kDa isshown to the right, as was determined using prestained SDS-PAGEstandards, Bio-Rad, CA.

FIG. 20 demonstrates Western blot of recombinant and native heparanasesfrom various origins using supernatant of hybridoma HP-117. Lanes 1 and2, 293 human kidney cells non-transfected and transfected withhpa-pCDNA, respectively (15 μg), lane 3, CHO cells stably transfectedwith pShpa (40 μg), lane 4, mock transfected CHO cells (40 μg), lane 5,purified recombinant heparanase produced by baculovirus infected insectcells (50 ng), lane 6, cell extracts of E. coli expressing recombinantheparanase (50 ng), lane 7, cell extract of human platelets (100 μg),lane 8, prestained SDS-PAGE standard, Bio-Rad, CA. Proteins wereseparated on 4-20% gradient SDS-PAGE and transferred to a nylon membrane(Amersham). Membrane was incubated with supernatant of hybridoma Hp117and detection was performed with alkaline phosphatase conjugatedanti-mouse IgG antibodies.

FIGS. 21 a-b demonstrate immunostaining of heparanase in CHO cells withpolyclonal antibodies. CHO cells transfected with the full length hpagene (21 a) were tested for overexpression of heparanase. Staining isdetected in the cytoplasm of transfected cells. In non transfected CHOcells (21 b), no staining of heparanase is detected.

FIGS. 22 a-b demonstrate immunostaining of heparanase in CHO cells withmonoclonal antibody HP-130. CHO cells transfected with the full lengthhpa gene (22 a) were tested for overexpression of heparanase. Stainingis detected in the cytoplasm of transfected cells. In non transfectedCHO cells (22 b), no staining of heparanase is detected.

FIGS. 23 a-c demonstrate immunostaining of heparanase in blood smearsfrom normal donor with monoclonal antibody HP-92. Heparanase is found inthe cytoplasm of neutrophils (23 a) and platelets (23 c) but is notdetected in lymphocytes (23 b) and monocytes (23 c).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is of heparanase specific molecular probes whichcan be used in research and medical applications. Specifically, thepresent invention can be used for the detection and monitoring ofmalignancies, metastasis and other, non-malignant conditions, efficiencyof therapeutic treatments, targeted drug delivery and therapy, usingheparanase specific molecular probes, such as anti-heparanase antibodies(both poly- and monoclonal) and heparanase gene (hpa) derived nucleicacids, including, but not limited to, PCR primers, antisenseoligonucleotide probes, antisense RNA probes, DNA probes and the like.

The principles and operation of the present invention may be betterunderstood with reference to the drawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangement of the components setforth in the following description or illustrated in the drawings. Theinvention is capable of other embodiments or of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting.

As shown in the Examples section below heparanase specific antibodiesand/or nucleic acids reveals in situ expression (protein and/ormessenger RNA) of heparanase in a variety of cells and tissues,especially in malignant cells and tissues, wherein the degree ofexpression corroborates with metastasis.

Therefore, according to one aspect of the present invention there isprovided a method of in situ detecting localization and distribution ofheparanase expression in a biological sample. The method comprises thestep of reacting the biological sample with a detectable heparanasespecific molecular probe and detecting the localization and distributionof the detectable heparanase specific molecular probe.

According to another aspect of the present invention, there is provideda method of detecting heparanase expression in a biological sample. Themethod comprises the step of reacting the biological sample with adetectable heparanase specific molecular probe and detecting thedetectable heparanase specific molecular probe. Protein and nucleic aciddot blot application are envisaged.

As used herein in the specification and in the claims section below, theterm “heparanase expression” refers mainly to the processes oftranscription and translation, resulting in a catalytically activeheparanase having endoglycosidase hydrolyzing activity which is specificfor heparin or heparan sulfate proteoglycan substrates, as opposed tothe activity of bacterial enzymes (heparinase I, II and III) whichdegrade heparin or heparan sulfate by means of β-elimination.

As used herein in the specification and in the claims section below, theterm “biological sample” refers to cells and tissues, including, but notlimited to cancer cells and tissues. The term further relates to bodyfluids, as further detailed below.

As used herein in the specification and in the claims section below, theterm “detectable heparanase specific molecular probe” and its equivalentterm “detectable heparanase molecular probe” both refer to a nucleicacid sequences hybridizable with heparanase encoding nucleic acid or toan anti-heparanase antibody capable of specifically binding heparanase.The nucleic acid sequence hybridizable with heparanase encoding nucleicacid is, for example, a synthetic oligonucleotide, an antisesnseheparanase RNA or heparanase DNA, and it is preferably labeled by thedetectable moiety.

As used herein in the specification and in the claims section below, theterm “detectable moiety” refers to any atom, molecule or a portionthereof, the presence, absence or level of which is directly orindirectly monitorable. One example include radioactive isotopes. Otherexamples include (i) enzymes which can catalyze color or light emitting(luminescence) reactions and (ii) fluorophores. The detection of thedetectable moiety can be direct provided that the detectable moiety isitself detectable, such as, for example, in the case of fluorophores.Alternatively, the detection of the detectable moiety can be indirect.In the latter case, a second moiety reactable with the detectablemoiety, itself being directly detectable is preferably employed. Thedetectable moiety may be inherent to the molecular probe. For example,the constant region of an antibody can serve as an indirect detectablemoiety to which a second antibody having a direct detectable moiety canspecifically bind.

As used herein in the specification and in the claims section below, theterm “antibody” refers to any monoclonal or polyclonal immunoglobulin,or a fragment of an immunoglobin such as sFv (single chain antigenbinding protein), Fab1 or Fab2. The immunoglobulin could also be a“humanized” antibody, in which murine variable regions are fused tohuman constant regions, or in which murine complementarity-determiningregions are grafted onto a human antibody structure (Wilder, R. B. etal., J. Clin. Oncol., 14:1383-1400, 1996). Unlike mouse or rabbitantibodies, “humanized” antibodies often do not undergo an undesirablereaction with the immune system of the subject. The terms “sFv” and“single chain antigen binding protein” refer to a type of a fragment ofan immunoglobulin, an example of which is sFv CC49 (Larson, S. M. etal., Cancer, 80:2458-68, 1997).

According to one embodiment of the invention the biological sample ismalignant, e.g., it is a solid tumor or hematopoietic tumor sample. Thesolid tumor can, for example, be of the types: carcinoma,adenocarcinoma, squameous cell carcinoma, teratocarcinoma, mesotheliomaor melanoma, which are shown hereinunder in the Examples section toexpress heparanase in good correlation to the degree of metastasis. Thehematopoietic tumor can, for example, be lymphoma or leukemia.

In some embodiments of the present invention the solid tumor is aprimary tumor, or a metastasis thereof, and it originates from an organsuch as, for example, liver, prostate, bladder, breast, ovary, cervix,colon, skin, intestine, stomach, uterus (including embryo) and pancreas.

As shown in the Examples section below, it was further found that bodyfluids (e.g., urine) of patients with certain conditions includecatalitically active heparanase. These conditions include myeloma,breast carcinoma, metastatic breast carcinoma, hemorrhagic nephritis,nephrotic syndrome, normoalbuminuric type I diabetes, microalbuminurictype I diabetes, kidney disorder, inflammation, sepsis, inflammatory andautoimmune disease.

Therefore, according to another aspect of the present invention there isprovided a method of detecting heparanase protein in a body fluid of apatient. The method comprises the steps of reacting the body fluid withan anti-heparanase antibody, either poly or monoclonal antibody, andmonitoring the reaction. The body fluid is, for example, plasma, urine,pleural effusions or saliva. Monitoring the reaction may be effected byhaving the antibody labeled with a detectable moiety, or to use itsconstant region as an inherent detectable moiety, to which a secondantibody which includes a detectable moiety can specifically bind.

Urine heparanase was detected in patients suffering from conditions suchas cancer, renal disease and diabetes. In some cases the renal diseasewas associated with diabetes.

According to a preferred embodiment of the present invention reactingthe body fluid with the anti-heparanase antibody is effected insolution. Alternatively, reacting the body fluid with theanti-heparanase antibody is effected on a substrate capable of adsorbingproteins present in the body fluid, all as well known in the art ofantibody based diagnosis.

As further shown in the Examples section below, RT-PCR proves useful indetecting the presence, absence or level of heparanase transcripts invarious biological samples.

Therefore, according to another aspect of the present invention there isprovided a method of detecting the presence, absence or level ofheparanase transcripts in a biological sample. The method comprises thefollowing steps. First, messenger RNA (e.g., as a component of totalRNA) is extracted from the biological sample, thereby a plurality ofmessenger RNAs are obtained. Second, the plurality of messenger RNAs arereverse transcribed into a plurality of complementary DNAs. Third, theplurality of complementary DNAs are contacted with a pair of heparanasespecific polymerase chain reaction (PCR) primers, nucleosidetriphosphates and a thermostable DNA polymerase (e.g., Thermophilusaquaticus DNA polymerase, native or recombinant) and a polymerase chainreaction is performed by temperature cycling, as well known in the art.Finally, the presence, absence or level of the polymerase chain reactionproduct is detected, e.g., by gel electrophoresis, by monitoring theincorporation of a detectable moiety into the product or any otherapplicable way, all as well known in the art.

As further shown in the Examples section below, protein blots andanti-heparanase antibodies prove useful in detecting the presence,absence or level of heparanase protein in various biological samples.

Therefore, further according to the present invention there is provideda method of detecting the presence, absence or level of heparanaseprotein in a biological sample. The method comprises the followingsteps. First, proteins are extracted from the biological sample, therebya plurality of proteins are obtained. The protein extract may be a crudeextract and can also include non-proteinacious material. Second, theproteins are size separated, e.g., by electrophoresis, gel filtrationetc. Fourth, the size separated proteins are interacted with ananti-heparanase antibody, either poly or monoclonal antibody. Finally,the presence, absence or level of the interacted anti-heparanaseantibody is detected. In case of gel electrophoresis the interactionwith the antibody is typically performed following blotting of the sizeseparated proteins onto a solid support (membrane).

In many cases it was shown that directly or indirectly (e.g., vialiposomes) linking a drug (e.g., anti cancerous drug, such as, forexample radio isotopes) to an antibody which recognized a proteinspecifically expressed by a tissue sensitive to the drug andadministering the antibody-drug complex to a patient, results intargeted delivery of the drug to the expressing tissue.

Therefore, according to yet another aspect of the present inventionthere is provided a method of targeted drug delivery to a tissue of apatient, the tissue expressing heparanase. The method comprises thesteps of providing a complex of a drug directly or indirectly linked toan anti-heparanase antibody and administering the complex to thepatient. External radio imaging is also envisaged, wherein the drug isreplaced with an imageable radio isotope. Endoscopic or laparoscopicimaging is also envisaged. In the latter cases the drug is typicallyreplaced by a fluorescence or luminescence substance. These proceduresmay, for example, be effective in finding/destroying micrometastases.

In other cases, it was shown that administering an antibody capable ofbinding epitopes associated with certain tissues provide means ofdestroying such tissues by an elicited immune response.

Therefore, according to another aspect of the present invention there isprovided a method of treating a patient having a condition associatedwith heparanase expression. The method comprises the step ofadministering an anti-heparanase antibody to the patient.

Further according to the present invention there is provided an antibodyelicited by a heparanase protein (e.g., recombinant) or an immunogenicalportion thereof, the antibody specifically binds heparanase. Theantibody can be a poly or monoclonal antibody. If it is poly clonal andproduced in vivo, it is preferably affinity purified, however crudeantibody preparations are also applicable, all as shown and described inmore detail in the Examples section hereinunder.

Preferably, the elicitation of the antibody is through in vivo or invitro techniques, the antibody having been prepared by a processcomprising the steps of, first, exposing cells capable of producingantibodies to the heparanase protein or the immonogenical part thereofand thereby generating antibody producing cells, second, fusing theantibody producing cells with myeloma cells and thereby generating aplurality of hybridoma cells each producing monoclonal antibodies, andthird, screening the plurality of monoclonal antibodies to identify amonoclonal antibody which specifically binds heparanase.

Further according to the present invention there is provided anoligonucleotide comprising a nucleic acid sequence specificallyhybridizable with heparanase encoding nucleic acid, be it heparanase DNAor RNA. The oligonucleotide may include natural nucleotides and/ornucleotide analogs, such as, but not limited to phosphorothioatedanalogs. Such oligonucleotides are readily synthesized provided that thesequence is known. Such oligonucleotides can be deduces, for example,from SEQ ID NOs: 1 and 3.

Further according to the present invention there are provided anantisense nucleic acid (RNA or DNA) molecule comprising a nucleic acidsequence specifically hybridizable with heparanase messenger RNA and asense nucleic acid (RNA or DNA) molecule comprising a nucleic acidsequence specifically hybridizable with heparanase antisense RNA.

EXAMPLES

Reference is now made to the following examples, which together with theabove descriptions, illustrate the invention in a non limiting fashion.

Experimental Methods and Materials

Cells: Cultures of bovine corneal endothelial cells (BCECs) wereestablished from steer eyes as previously described (19, 31). Stockcultures were maintained in DMEM (1 gram glucose/liter) supplementedwith 10% newborn calf serum, 5% fetal calf serum (FCS). bFGF (1 ng/ml)was added every other day during the phase of active cell growth (14,15).

Preparation of sulfate labeled substrates: BCECs (second to fifthpassage) were plated into 35 mm tissue culture plates at an initialdensity of 2×10⁵ cells/ml and cultured in DMEM supplemented with 10% FCSand 5% dextran T-40 for 12 days. Na₂ ³⁵SO₄ (25 μCi/ml) was added on day1 and 5 after seeding and the cultures were incubated with the labelwithout medium change. The subendothelial ECM was exposed by dissolving(5 min, room temperature) the cell layer with PBS containing 0.5% TritonX-100 and 20 mM NH₄OH, followed by four washes with PBS. The ECMremained intact, free of cellular debris and firmly attached to theentire area of the tissue culture dish (14, 15, 20).

To prepare soluble sulfate labeled proteoglycans (peak I material), theECM was digested with trypsin (25 μg/ml, 6 hours, 37° C.), the digestwas concentrated by reverse dialysis, applied onto a Sepharose 6B gelfiltration column and the high molecular weight material (Kav<0.2, peakI) was collected (32). More than 80% of the labeled material was shownto be composed of heparan sulfate proteoglycans (11).

Heparanase activity: Cells (1×10⁶/35-mm dish), cell lysates orconditioned medium were incubated on top of ³⁵S-labeled ECM (18 hours,37° C.) in the presence of 20 mM phosphate or phosphate citrate buffer(pH 6.2). Cell lysates and conditioned media were also incubated withsulfate labeled peak I material (10-20 μl). The incubation medium wascollected, centrifuged (18,000 g, 4° C., 3 min), and sulfate labeledmaterial was analyzed by gel filtration on a Sepharose CL-6B column(0.9×30 cm). Fractions (0.2 ml) were eluted with PBS at a flow rate of 5ml/hour and counted for radioactivity using Bio-fluor scintillationfluid. The excluded volume (V_(o)) was marked by blue dextran and thetotal included volume (V_(t)) by phenol red. The latter was shown tocomigrate with free sulfate (11, 20). Degradation fragments of HS sidechains were eluted from Sepharose 6B at 0.5<Kav<0.8 (peak II) (11, 20).A nearly intact HSPG released from ECM by trypsin was eluted next toV_(o) (Kav<0.2, peak I). Recoveries of labeled material applied on thecolumns ranged from 85 to 95% in different experiments.

Construction of heparanase expression vector: A BamHI-KpnI 1.3 kbfragment (nucleotides 450-1721 of the hpa sequence, SEQ ID NOs: 1 and 3,U.S. patent application Ser. No. 08/922,170) was cut out from pfasthpaand cloned into pRSET-C bacterial expression vector (Invitrogen). Theresulting recombinant plasmid pRSEThpaBK encodes a fusion proteincomprised of His tag, a linker sequence and amino acids 130-543 of theheparanase protein (SEQ ID NOs: 2 and 3).

A 1.6 kb fragment of hpa cDNA was amplified from pfasthpa (a hpa cDNAcloned in pfastBac, see U.S. patent Ser. No. 08/922,170), by PCR usingspecific sense primer: (Hpu-550Nde)-5′-CGCATATGCAGGACGTCGTGGACCTG-3′(SEQ ID NO:4) and a vector specific antisense primer: (3′pFast)5′-TATGATCCTCTAGTACTTCTCGAC-3′ (SEQ ID NO:5). The upper primerintroduced an NdeI site and an ATG codon preceding nucleotide 168 ofhpa. The PCR product was digested by NdeI and BamHI and its sequence wasconfirmed. pRSEThpaBK was digested with NdeI and BamHI and ligated withthe NdeI-BamHI hpa fragment. The resulting plasmid, designatedpRSEThpaS1, encoded an open reading frame of 508 amino acids (36-543) ofthe heparanase protein, lacking the N-terminal 35 amino acids which arepredicted to be a signal peptide. Expression constructs were introducedinto E. coli BL21(DEL3)pLysS cells (Stratagene), according to supplier'sprotocol.

Preparation of antigen: E. coli cells harboring the recombinant plasmidwere grown at 37° C. overnight in Luria broth containing ampicillin andchloramphenicol. Cells were diluted 1/10 in the same medium, and thecultures were grown to an OD600 of approximately 0.5.Isopropyl-thiogalactoside (IPTG) (Promega) was added to a finalconcentration of 1 mM and the culture was incubated at 37° C. for 3hours. Cells from induced cultures were cooled on ice, sedimented bycentrifugation at 4,000×g for 20 minutes at 4° C., and resuspended in0.5 ml of cold phosphate-buffered saline (PBS). Cells were lysed bysonication, and cell debris was sedimented by centrifugation at 10,000×gfor 20 minutes. The resulting pellet was analyzed by 10% SDS-PAGE. Thegel was stained with 1×PBS coomassie blue and the band of 45 kDa whichcontained the recombinant heparanase was cut out and crashed through aneedle (21G) attached to a syringe. For immunization of mice, thecrashed gel was incubated in PBS overnight at 4° C. and the proteindiffused into the buffer was collected. Rabbits ware injected with gelhomogenate.

The 55 kDa protein (508 amino acids) was purified from E. coli inclusionbodies by preparative SDS-PAGE, using a Model 491 Prep Cell (Bio-Rad)which is designed to purify proteins from complex mixtures by continuouselution electrophoresis. This antigen was used for ELISA screening.

Immunization—polyclonal antibodies: Two rabbits (designated 7640 and7644) were immunized each with 200 μg of protein emulsified with equalvolume of complete Freund's adjuvant. An equal amount of proteinemulsified with incomplete Freund's was injected to each rabbit twoweeks following the first injection and again after another four weeks.Ten days after the third injection the rabbits were bled and serum wasexamined for reactivity with recombinant heparanase. Four weeks afterbleeding another boost was injected and 10 days later blood wascollected.

Immunization—monoclonal antibodies: 6 to 8 weeks old female Balb/C micewere each immunized intradermally with 50 μg recombinant heparanaseemulsified in 50 μl PBS complete Freund's adjuvant. Two to three weekslater the same amount of the emulsion was injected subcutaneously orintradermally at multiple sites in incomplete Freund's adjuvant. After 3weeks 25 μg antigen in aqueous solution was injected intrapertonealy.7-10 days later animals were bled and the titer of the relevantantibodies was determined. 3-4 weeks after the last boost, one or twoanimals were injected intraperitoneal with 20 μg of soluble antigen (inPBS) and 3-4 days later spleens were removed.

Fusion and cloning: The spleens of immunized mice were ground,splenocytes were harvested and fused with the NSO myeloma cells byadding 41% PEG. Hybridoma cells were grown in HAT-selective DMEM growthmedia containing 15% (v/v) HS (Beit Haemek), 2 mM glutamine,Pen-Strep-Nystatin solution (Penicillin: 10,000 units/ml, Streptomycin:10 mg/ml, Nystatin: 1,250 units/ml), at 37° C. in 8% CO₂ containingatmosphere. Hybridoma cells were cloned by limiting dilution. Hybridomasproducing Mabs to human heparanase were identified by reactivity withsolid-phase immobilized human heparanase.

ELISA: Falcon polyvinyl plates were coated with 50 ng/well ofbaculovirus derived human heparanase (native) and 100 ng/well of E. coliderived human heparanase (55 kDa-non-active) in PBS (pH 7.2) overnightat 40° C. Hybridoma tissue culture supernatants were added to the wells,and incubated at room temperature for 2 hours. Binding of Mabs was thendetected by incubation with HRP-conjugated goat anti mouse IgG (Fabspecific) (Sigma), followed by development in o-phenylenediaminesubstrate (Sigma) and measurement of absorbencies at 450 nm. PBS with0.05% Tween was used to wash the plates between incubations. Polyclonalrabbit anti human heparanase was used as positive control and negativecontrol included coating with PBS or irrelevant supernatant.

Affinity purification of polyclonal antibodies: 200 μg of recombinantheparanase were separated on 10% SDS-PAGE. Following electrophoresisprotein was transferred to a nitrocellulose membrane (Schleicher &Scuell). Membrane was stained with Ponceau S and the heparanase band wascut out. The membrane strip was blocked for 2 hours in TBS containing0.02% Tween 20 and 5% skim milk. Antiserum was diluted 1:3 in blockingsolution and incubated with the membrane for 16 hours. Membrane stripwas washed with 0.15 M NaCl for 20 minutes and then with PBS foradditional 20 minutes. Antibodies were eluted with 0.2 M glycine, 1 mMEDTA pH 2.8 for 20 minutes at room temperature, and then neutralized byaddition of 0.1 volumes of 1 M Tris pH 8.0 and 0.1 volumes of 10×PBS.NaNO₃ was added to a final concentration of 0.02%.

Western blot: Proteins were separated on 4-20%, or 8-16% polyacrylamideready gradient gels (Novex). Following electrophoresis proteins weretransferred to Hybond-P nylon membrane (Amersham) (350 mA/100V for 90minutes). Membranes were blocked in TBS containing 0.02% Tween 20 and 5%skim milk for 1-16 hours, and then incubated with antisera diluted inblocking solution. Blots were then washed in TBS-Tween, incubated withappropriate HRP-conjugated anti mouse/anti rabbit IgG, and developedusing ECL reagents (Amersham) according to the manufacturer'sinstructions. Alternatively, an alkaline phosphatase conjugatedanti-mouse/anti-rabbit IgG antibodies were used as secondary antibodiesand blots were developed with FAST™ BCIP/NBT (Sigma) according to thesupplier's instructions.

Expression of the heparanase gene in various cell types and tissues(RT-PCR): RT-PCR was applied to evaluate the expression of the hpa geneby various cell types. For this purpose, total RNA was reversetranscribed and amplified, using the following cDNA primers: Humanhpa—Hpu-355 5′-TTCGATCCCAAGAAGGAATCAAC-3′ (SEQ ID NO:6) andHpl-229-5′-GTAGTGATGCCATGTAACTGAATC-3′ (SEQ ID NO:7).

Expression pattern of the heparanase gene transcript (in situhybridization). In situ hybridization enables determination of thedistribution of hpa transcripts in normal and malignant tissues. Forthis purpose, thin sections of biopsy specimens were processed for insitu hybridization and hybridized with an antisense RNA probe to the hpagene. The experiments have the resolution power to unambiguouslyidentify the expressing cell type, be they tumor cells, tissuemacrophages, mast cells or platelets. Sections were treated withproteinase K to expose the target RNA and to block non specific bindingsites before addition of the probe (34). For in situ hybridization, twodigoxigenin labeled probes were prepared, one in the sense direction andthe other in the anti-sense direction. They were both transcribed from afragment of about 624 bp of the hpa cDNA sequence (nucleotides 728-1351,SEQ ID NOs: 1 and 3) cloned in to the EcoRI-HindIII sites of thetranscription vector pT3T7-Pac (a modified vector derived from pT3T7,Pharmacia), using T3 (for antisense) or T7 (for sense) RNA polymerase,according to the suppliers protocol. Slides were hybridized underappropriate conditions with the labeled probe and the hybridized probeis visualized using calorimetric reagents (NBT & BCIP) (34). Reactionswere stopped when the desired intensity has been reached.

In situ detection of heparanase by antibodies: hpa-transfected and nontransfected CHO cells were plated on 8-chamber tissue culture slides(Nunc). Cells were fixed in 95% ethanol, 5% acetic acid for 5 minutes at−20° C. Cells were permeabilized using permeabilization buffer (20 mMHEPES, pH 7.4; 300 mM Sucrose; 50 mM NaCl; 3 mM MgCl₂; 0.5% TritonX-100) for 4 minutes at 4° C. Endogenous peroxidases were blocked using0.3% H₂O₂ in methanol and non specific binding sites were blocked using5% horse serum in PBS. Monoclonal anti-heparanase antibody (supernatantof hybridoma) was applied and incubated with the cells overnight at roomtemperature. Antibody was washed away and biotinylated secondaryantibody (horse-anti mouse, Vector, Vectastain ABC system) was added for30 minutes at room temperature. Immunostaining was detected using DiAmino Benzidine and H₂O₂ (Sigma tablets) until desiredstaining-intensity was achieved. Slides were counterstained with Mayer'shematoxylin. Immunostaining with polyclonal antibodies was performedunder the same conditions, affinity purified antibody was used at 1:500dilution. Biotinylated horse anti-rabbit was used as a secondaryantibody (Vector, Vectastain ABC system). Blood smears were preparedfrom a healthy donor. Fixation and staining were performed as describedabove.

Experimental Results

Differential expression of the hpa gene in human breast carcinoma andbreast carcinoma cell lines: Semi-quantitative RT-PCR was applied toevaluate the expression of the hpa gene by human breast carcinoma celllines exhibiting different degrees of metastasis (35, 36). While thenon-metastatic MCF-7 breast carcinoma line failed to express theexpected 585 bp cDNA of the hpa gene (FIG. 1, lane 1), moderate (MDA231, FIG. 1, lane 2) and highly (MDA 435, lane 3) metastatic breastcarcinoma cell lines exhibited a marked increase in hpa gene expression.The differential expression of the hpa gene was reflected by a similardifferential pattern of heparanase activity. As demonstrated in FIG. 2a, lysates of MCF-7 cells exhibited little or no heparanase activity, ascompared to a moderate and high activity expressed by MDA-231 andMDA-435 cells, characterized by moderate and high metastatic potentialin nude mice, respectively.

The same pattern of hpa gene expression and heparan sulfate degradingactivity was observed in another model of breast cancer. While the ZR75(=MCF10A) displastic breast cell line originated from fibrocystic breastepithelial cells showed little or no expression of the hpa gene (FIG. 1,lane 4), Ha-ras transfected ZR75 cell line (MCF10AT and MCF10AT3B)expressed the hpa gene (lanes 5 and 6) in correlation with theirmetastatic potential. The highly metastatic MCF10AT3B cells were derivedfrom the third generation of xenografted tumors (36). The heparanaseactivity expressed by these cell lines was in correlation with theirmetastatic behavior (FIG. 2 b).

In subsequent experiments, sense and antisense deoxigenin labeled RNAprobes (600 bp fragment of the hpa cDNA) were employed to screenarchivial paraffin embedded human breast tissue for expression of thehpa gene transcripts by in situ hybridization.

As shown in FIGS. 3 a-f, massive expression of the hpa gene was observedin invasive breast carcinoma (3 a) and breast adenocarcinoma (3 c). Thehpa gene was already expressed by differentiated epithelial cells ofpre-malignant fibrocystic breast (3 b) and in breast carcinoma tissuesurrounding the area of tumor necrosis where little or no staining wasobserved (3 d). Unlike the malignant tissue, normal breast tissue failedto express the hpa transcript as revealed by the lack of staining intissue derived from reduction mammoplasty, both by the antisense (3 e)and sense (3 f) hpa probes.

Altogether, these results demonstrate a preferential expression of thehpa gene malignant breast carcinoma cells, indicating a potentialapplication in early diagnosis of the disease, particularly in view ofthe positive staining detected already in the fibrocystic stage.

Human prostate and bladder carcinomas: Differential expression of thehpa mRNA was also suggested by RT-PCR analysis of several human prostateand bladder carcinoma cell lines. As demonstrated in FIG. 4, both DU145(lane 1) and PC3 (lane 2) human prostate cell lines showed highexpression of the hpa mRNA in contrast to lack of, or non-detectable,expression in a biopsy of normal adult prostate tissue (lane 3).Similarly, as demonstrated in FIG. 5, highly metastatic variant (T50) ofthe non-metastatic MBT2 human bladder carcinoma cell line, exhibited amuch higher expression of the hpa gene (lane 2) as compared with theMBT2 cell line (lane 1). This difference was also reflected by highheparanase activity secreted into the culture medium of the aggressiveT50 cells, as compared to no detectable activity in the medium of theparental MBT2 cells (FIGS. 6 a-c). Again, the observed differentialexpression of the hpa gene and enzyme activity points toward potentialapplication in the diagnosis of metastatic human prostate and bladdercarcinomas.

Mouse melanoma and T-lymphoma: Differential expression of the hpa mRNAand heparan sulfate degrading activity, correlated with the metastaticpotential in mice was also demonstrated in studies with mouse B16melanoma and T-lymphoma. In fact, the melanoma (9, 37) and lymphoma (11)cell systems were the first experimental systems pointing toward animportant role of heparanase in tumor cell invasion and metastasis. Ourcloning of the hpa cDNA, encoding for the heparanase enzyme, provides,for the first time, an evidence that the difference in enzymaticactivity is due primarily to a preferential expression of the hpa geneby highly metastatic tumor cells. Thus, as demonstrated in FIGS. 5 and7, the highly metastatic ESb lymphoma (FIG. 5, lane 4) and B16-F10melanoma (FIG. 7, lane 1) cell lines, expressed the hpa gene to a muchhigher extent as compared to the parental low metastatic Eb lymphoma(FIG. 5, lane 3) and B16-F1 melanoma (FIG. 7, lane 2) cells. Therespective high and low levels of heparanase activity by these celllines were reported in earlier studies (9, 11, 37).

Human melanoma: Preferential expression of the hpa gene and enzymeactivity was also observed in cells derived from biopsies of humanmelanoma and normal nevus tissue. Biopsy specimens of malignant melanomaare routinely processed for cell culture in the department of Oncology(Hadassah Hospital, Jerusalem) for immunotherapy purposes. Culturedcells derived from 16 out of 16 patients (see also Table 1, below)expressed the hpa gene, as revealed by RT-PCR (FIG. 8 a, lane 1, arepresentative patient). Melanoma cells derived from 3 of these patientswere tested for degradation of soluble heparan sulfate proteoglycans andwere found to be highly active (FIG. 8 b). In contrast, cells derivedfrom a non-malignant nevus tissue showed no detectable expression of thehpa mRNA (FIG. 8 a, lane 2) and no enzyme activity (FIG. 8 b).

Similar results were obtained using archivial paraffin embedded biopsyspecimens and in situ hybridization. Again, cytoplasmic labeling of thehpa mRNA was observed in tissue sections of metastatic specimens derivedfrom 3 different patients with malignant melanoma (FIGS. 9 a and 9 c-d),but not from a non-malignant nevus (FIG. 9 b). Altogether, these resultsimply a potential use of hpa specific primers, nucleic acid probes andantibodies in early diagnosis of melanoma metastasis.

Human liver carcinoma: The heparanase enzyme was first purified in ourlaboratory from a human hepatoma cell line (Sk-Hep-1). In fact, aminoacid sequences derived from the purified hepatoma heparanase were usedto clone the hpa gene. In situ hybridization studies revealed an intenseexpression of the hpa gene in tissue sections derived from humanheaptocellular carcinoma (FIGS. 10 a-b) and liver adenocarcinoma (FIG.10 c). The hpa mRNA was not expressed by adult normal liver tissue (FIG.10 d). It was expressed, however, in embryonic human liver (FIG. 10 e).Each of these examples clearly supports the use of heparanase specificmolecular probes as tools for early diagnosis of human cancer and itsspread and response to anti-cancer treatments.

Other human tumors: A preferential expression of the hpa gene wasclearly observed by in situ hybridization performed with biopsyspecimens of several different human carcinomas in comparison with theirnormal tissue counterparts. As demonstrated in FIGS. 11 a-f, an intenseexpression of the hpa gene was observed in tissue sections derived fromadenocarcinoma of the ovary (FIG. 11 a), squameous cell carcinoma of thecervix (FIG. 11 c), and colon adenocarcinoma (FIG. 11 e). In contrast,there was little or no expression of the hpa mRNA in human tissuesections derived from normal ovary (FIG. 11 b), cervix (FIG. 11 d) andsmall intestine (FIG. 11 f). The few cells stained in the normal tissuespecimens were single infiltrating macrophages and neutrophils.

Positive staining of the hpa gene was also clearly seen inadenocarcinoma of the stomach (FIG. 12 a), teratocarcinoma (FIG. 12 b),well differentiated endometrial adenocarcinoma (FIG. 12 c),adenocarcinoma of the pancreas (FIG. 12 d), and mesothelioma (FIG. 12e). Each of these examples clearly supports the use of heparanasespecific molecular probes as tools for early diagnosis of human cancerand its spread and response to anti-cancer treatments.

Human leukemia and lymphoma: We have previously applied time consumingmeasurements of heparanase activity and demonstrated that heparanase isexpressed and readily secreted by acute and chronic human myeloidleukemic cells (AML and CML), but not by chronic lymphocytic leukemiccells (CLL). The availability of heparanase specific primers enables amore sensitive and rapid determination of hpa gene expression by humanleukemia and lymphoma cells. For this purpose, peripheral white bloodcells (derived from patients with leukemia and lymphoma) were purifiedon Ficoll-hypack and subjected to total RNA isolation and RT-PCRdetermination of the hpa mRNA. Altogether, cells of 69 patients weretested. Representative patients are presented in FIGS. 13 a-b and theresults are summarized in Table 1 below. Cells from 31 out of 31patients with CLL showed no detectable expression of the hpa gene (FIG.13 a, lanes 1-5, FIG. 13 b, lanes 2, 7, 10 and 12) regardless of thestage of the disease. Similar results were obtained with cells from 4out of 4 patients with non-Hodjkin lymphoma (NHL) (FIG. 13 b, lanes 5and 6). Both the CLL and NHL cells represent primarily differentiated Bcells. In contrast, the hpa mRNA was expressed by cells derived from 14out of 14 patients with AML (FIG. 13 b, lane 11). These cells representundifferentiated myeloblasts of neutrophils and monocyte origin. The hpamRNA was expressed in cells of 1 out of 3 patients with CML, and 2 outof 2 patients with acute lymphocytic leukemia. Surprisingly, umbilicalcord blood derived white blood cells showed little (one case) or noexpression (13 additional cases) of the hpa gene in different cord bloodsamples (FIG. 14, Table 1, below). These cord blood preparations areenriched with hematopoietic stem cells. Studies with established celllines (FIG. 15) revealed no expression of the hpa mRNA in Burkitt Blymphoma (i.e., Raji, Daudi, DG-75, lanes 2-4, respectively), as opposedto mature normal B (Ebv transformed) lymphoblastoid cell line (i.e.,monga, FIG. 15, lane 1) and erythroleukemia (K-562, lane 5).

Apparently, heparanase expression can distinguish between differentiatedB cell lymphoma (CLL and NHL) and undifferentiated myelocytic andlymphoblastoid leukemia (AML and ALL) (Table 1). The lack of hpa geneexpression by umbilical cord white blood cells may enable to distinguishbetween early normal white blood cells (hpa negative) and early leukemiccells (hpa positive). Furthermore, the presence of heparanase maydistinguish between early lymphatic leukemic cells (hpa positive) andlate B leukemia and lymphoma cells (hpa negative).

TABLE 1 Expression of hpa mRNA (RT-PCR) in human leukemia, lymphoma andmelanoma Type # of patients # hpa positive # hpa negative CLL 31 0 31AML 14 14 0 ALL 2 2 0 CML 3 1 2 NHL 4 0 4 Cord blood 14 1 13 Melanoma 1616 0 Nevus (normal) 3 0 3

Heparanase activity in the urine of cancer patients: In an attempt toelucidate the involvement of heparanase in tumor progression and itsrelevance to human cancer, we screened urine samples for heparanaseactivity. Heparanase activity was determined by incubation of urine withsoluble sulfate labeled proteoglycans obtained by trypsin digestion ofmetabolically Na₂ ³⁵SO₄ labeled subendothelial extracellular matrix.Heparanase activity resulted in conversion of a high molecular weight(MW) sulfate labeled substrate into low MW heparan sulfate degradationfragments as determined by gel filtration analysis. Heparanase activitywas detected in the urine of 21 (renal cell carcinoma, breast carcinoma,rabdomyosarcoma, stomach cancer, myeloma) out of 157 cancer patients.Three examples are given in FIGS. 16 a-c. High levels of heparanaseactivity were determined in the urine of patients with an aggressivedisease (primarily breast carcinoma, FIGS. 16 b-c, multiple myeloma,FIG. 16 a) and there was no detectable activity in the urine of healthydonors (FIG. 16 d). A more sensitive ELISA is expected to detect theheparanase protein at early stages of the disease. Urine may alsocontain heparanase inhibitors (i.e., GAGs) and hence an activity assaymay under estimate the number of patients with positive urinaryheparanase protein.

Heparanase activity in the urine of diabetic patients: Reduction inglomerular basement membrane (GBM) heparan sulfate proteoglycan (HSPG)is responsible for the microalbuminuria and proteinuria of diabeticnephropathy. We identified heparanase activity in cultured rat mesangialcells and postulated that the reduction in glomerular HSPG is secondaryto increased glomerular heparanase activity and that the latter will bemanifested by an increase in urinary heparanase. Urinary heparanaseactivity was tested in samples from 70 patients with type I diabetes andin 40 sex and age matched controls, as described above. The results aresummarized in Table 2 below. Fifty patients were normoalbuminuric (NA)while 20 had microalbuminuria (MA). Urinary heparanase activity wasdetected in 13 of 70 (19%) diabetic patients while it was absent in thecontrol group (p=0.002). Sixteen percent of the NA patients and 25% ofthe MA patients showed urinary heparanase activity (FIGS. 16 g-h).Interestingly, over 80% of the heparanase positive patients werefemales. Heparanase positive patients had significantly higher bloodglucose (p=0.0005) and HbA1C (p=0.03) levels compared with heparanasenegative diabetic patients. This is the first study suggesting a rolefor heparanase in the pathogenesis of diabetic nephropathy. Urinaryheparanase may be an early marker for renal involvement in type Idiabetic patients, anteceding MA. The presence of heparanase activity inthe urine of normo and microalbuminuric IDDM (insulin dependent diabeticmellitus) patients, is most likely due to diabetic nephropathy, the mostimportant single disorder leading to renal failure in adults.

TABLE 2 Heparanase activity in urine of IDDM patients No. of AveragedDisease Blood Heparanase patients Age Sex duration pressure GFR positiveNormo- 50 26.2 ± 8.5 26 males 16.5 ± 7.3 112 ± 17 134 ± 25 8/50 (16%)albuminuria years 24 females years ml/min/1.73 m² Microalbuminuria 2026.5 ± 11.2 10 males 14.5 ± 7.9 115 ± 13 128 ± 26 5/20 (25%) years 10females years ml/min/1.73 m²

Repeated determination of urinary heparanase in 9 IDDM patients yieldedsimilar results (6 negative and 3 positive) to the initial analysisperformed 3 months earlier. Our results suggest that heparanase activitymay play a role in the regulation of the number of HSPG anionic sites inthe GBM and hence may modulate the permselective properties of theglomerular basement membrane.

Heparan sulfate contributes to the assembly and integrity of the ECMthrough binding to various ECM molecules such as collagen, laminin,fibronectin, thrombospondin and tenascin. Cleavage of heparan sulfatemay therefore result in disassembly of the ECM leading to a loss of itsbarrier properties. We have identified heparanase activity expressed bymesanglial cells (not shown). Once heparanase is secreted by stimulatedmesangial cells it will degrade heparan sulfate in the GBM thus allowingits passage into the urinary space.

Heparanase activity was also detected in the urine of proteinuricpatients not suffering from diabetes (FIGS. 16 e-f). These includedpatients with focal segmental glomerulosclerosis, minimal changenephrotic syndrome and congenital nephrotic syndrome, thus indicatingthat the involvement of heparanase in the generation of proteinuria maynot be limited to diabetic nephropathy. Urinary heparanase activityseems to be detected more frequently as the degree of proteinuriaincreases. Active heparanase was detected in the urine of 15% ofnormoalbuminuric and 25% microalbuminuric type I diabetic patients. Theprevalence reached 48% in a group of 28 macroalbuminuric patients withNIDDM.

Diabetic nephropathy, occurring in approximately 30% of patients withtype I diabetes, is a major cause of end stage renal disease. Theinability to discriminate the subpopulation that will develop renaldamage prior to the appearance of microalbuminuria, 10-15 yearsfollowing the diagnosis of diabetes, prevents us from significantlychanging the devastating natural history of the disease. Urinaryheparanase activity is a distinguishing feature, occurring in 30-35% ofnormoalbuminuric females, within an otherwise homogenous group ofpatients.

This is the first result suggesting a role for heparanase in thepathogenesis of proteinuria in type I diabetes. Obviously, measurementsof urinary heparanase activity is both time consuming and not sensitiveenough. Moreover, we have demonstrated the presence of an inhibitor ofmammalian heparanase in the urine of normal individuals. The nature ofthis inhibitory substance, possibly urinary glycosaminoglycans iscurrently being studied. Urinary heparanase activity is therefore theresult of a balance between the presence in the urine of the enzyme andits inhibitor(s). Immunodetection of the heparanase protein is thereforea more sensitive and straightforward approach for diagnostic purposes.Altogether, our results clearly indicate that anti-heparanase antibodiesthat identify the heparanase antigen can be applied for early diagnosisof cancer metastasis and renal diseases. As discussed above, it isconceivable that heparanase may overcome the filtration barrier of theglomerular basement membrane and ECM simply by virtue of its ability todegrade the HS moieties that are held responsible for theirpermeaselective properties. Urinary heparanase is therefore expected toreflect the presence of heparanase in the circulation and hence be asensitive marker for metastatic, inflammatory and kidney disease. Ofparticular significance is the potential ability to follow the course oftumor progression and spread, response to anti-cancer treatments, andpossible relapse of the disease in a given patient. Targeted drugdelivery and therapy are another aspect of the use for such antibodies.

Anti-heparanase polyclonal antibodies: Antisera from two immunizedrabbits were examined by western blot for reactivity with varioussegments of recombinant heparanase expressed in E. coli and with theBaculovirus expressed heparanase (FIGS. 17 a-b). In both cases, thepolyclonal antibody recognized proteins of the expected size in E. coliderived recombinant heparanase, about 60 kDa for the entire open readingframe (lanes 2), about 45 kDa for the 414 amino acids BamHI-KpnI hpafragment (lanes 3) and 35 kDa for the 302 amino acids encoded by aBamHI-HindIII hpa fragment (lanes 4). A protein of approximately 65 kDawas recognized in the medium of Sf21 insect cells infected withrecombinant Baculovirus pFhpa (lanes 7).

The specificity of affinity purified polyclonal antibodies wasdetermined by Western blot with recombinant heparanase expressed invarious expression systems, baculovirus infected insect cells, the yeastPichia pastoris and CHO cells transfected with the hpa cDNA. For detailsabout the CHO and Pichia clones see U.S. patent application Ser. No.09/071,618, which is incorporated by reference as if fully set forthherein.

The specificity of the purified antibody is demonstrated in FIG. 18. Thepurified antibody identified a single about 65 kDa protein expressed byPichia pastoris (FIG. 18, lane 4), and a major band of similar sizeexpressed by Sf21 cells infected with recombinant baculovirus (FIG. 18,lane 1). In a CHO stable transfected clone, 65 kDa and 50 kDa bands aredetected (FIG. 18, lane 3) as compared with the negative control (FIG.18, lane 2). In several experiments the two forms of the recombinantheparanase were identified, the higher form appeared as 60 to 65 kDa andthe lower form as 45 to 50 kDa. Antibody 7644 was more specific anddetected mainly the bands of the recombinant heparanase. 7460 detectedseveral other cross reactive bands.

As shown in FIG. 19 a, crude polyclonal antibodies recognized multiplebands in human platelets (lanes 2 and 3) and neutrophils cell extracts(lanes 4 and 5), as well as mouse melanoma cell line B16 (lanes 6 and7). However, as shown in FIG. 19 b, affinity purified antibodiesrecognized the 65 kDa and 50 kDa forms of heparanase purified fromplacenta (lane 1), two major bands in platelets extract, an upper bandof approximately 50 kDa which corresponds with the lower band of thepurified protein and a lower band of about 30 kDa (lanes 2 and 3). The50 kDa protein appears in mouse melanoma cells as well as two bands of ahigher molecular weight and several minor bands, which represent crossreactive proteins or other species of heparanase (lanes 6 and 7).

Monoclonal antibodies: Eight hundreds hybridomas, generated following 3fusions were screened by ELISA for reactivity against human heparanase(native and denatured). Eight positive hybridomas were selected. Table 3below summarizes the characteristics of the 8 hybridomas.

TABLE 3 Relative reactivity of hybridomas supernatants with native anddenatured recombinant human heparanase ELISA Hybridoma Native DenatureWestern blotting HP-6 − + n.d. HP-40 +++ ++ n.d. HP-45 + ++ n.d. HP-92++ +++ n.d/ HP-117 ++++ +++ 60, 45, 42 kDa HP-130 ++++ +++ n.d. HP-239++++ +++ n.d. HP-303 − ++ n.d. n.d.—not determined

Immunoblot of native and recombinant heparanase expressed in variouscell types was performed using the supernatant of hybridoma HP-117 (FIG.20). A major band of approximately 50 kDa was detected in extract ofstably transfected CHO cells (lane 3) and in platelets extract (lane 6).This band is also detected in transfected 293 cells as compared to thenegative control (lanes 2 and 1 respectively). A band of approximately42 kDa was observed in all mammalian cell extracts, including thenegative control. This band probably represent a cross reactive proteinor an endogenous form of heparanase. The 65 kDa recombinant heparanasepurified from medium of baculovirus infected insect cells is clearlyobserved in lane 5 as well as a band of 53 kDa in lane 6 which is theexpected size of the 508 amino acids heparanase polypeptide expressed inthe E. coli. cells

Both polyclonal and monoclonal antibodies were used successfully fordetection of heparanase in intact cells by immunohistochemistry.Polyclonal antibodies showed specific staining of CHO cells transfectedwith pShpaCdhfr expression vector as described in patent U.S. patentapplication Ser. No. 09/071,618, which is incorporated by reference asif fully set forth herein, as compared with no staining of thenon-transfected CHO cells (FIGS. 21 a-b). Similar results were obtainedwith several monoclonal antibodies. FIGS. 22 a-b demonstrate thespecific staining of heparanase in the cytoplasm of transfected CHOcells, with supernatant of hybridoma HP-130. No staining was observed innon-transfected cells. Monoclonal antibody HP-92 showed a specificstaining of neutrophils and platelets in blood smear of a healthy donor(FIGS. 23 a-c). This expression pattern is consistent with the highlevels of heparanase activity characteristic of these cells.

Availability of anti-heparanase antibodies will enable development ofimmunological assays for screening tissue and body fluids forheparanase. An ELISA will provide a more sensitive and convenient meansof detection as compared to the currently available assays of heparanaseactivity which do not appear sensitive enough for the detection of theenzyme in non-concentrated plasma and body fluids.

ELISA will provide a powerful diagnostic tool for quantitativedetermination of heparanase concentrations in serum, plasma, urine andother biological fluids. Although platelets and activated cells of theimmune system (11) can express heparanase activity under certainconditions, we have detected little or no heparanase activity in normalhuman plasma. The possibility arises that with cancer patients,particularly those with leukemia and lymphoma, heparanase is secretedinto the blood stream. In fact, our studies indicate that both acute andchronic human myeloid leukemic cells (AML and CML), but not chroniclymphocytic leukemic cells (CLL), secrete substantial amounts ofheparanase during short incubation in PBS at 4° C.

As described above, elevated levels of heparanase were detected in serafrom metastatic tumor bearing animals and melanoma patients (13) and intumor biopsies of cancer patients (15). High levels of heparanaseactivity were measured in the urine of patients with aggressivemetastatic disease and there was no detectable activity in the urine ofhealthy donors.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

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1. A method of detecting expression of a human heparanase gene whichcomprises a polynucleotide as set forth in SEQ ID NO: 1 in a humanindividual suspected of suffering from a blood cancer, the methodcomprising using an anti-heparanase antibody capable of bindingheparanase encoded by SEQ ID NO: 1 for monitoring heparanase proteinexpression of said human heparanase gene in white blood cells of saidindividual in vitro.